In the December 1993 meeting between representatives of the former US SSC efforts and the CMS management, Inner Tracking was one of the areas identified by the CMS collaboration where participation by US groups would be very important. That was reaffirmed at the February CMS meeting at UCLA, and an explicit request for assistance in the area of Inner Tracking was made by the CMS spokesman, Michel Della Negra, at the April 6-7 LoI meeting held at Fermilab.
The Inner Tracking detector is one of the cornerstones of the overall CMS effort, and will play major roles in all the physics searches that will be undertaken by the CMS group. The Inner Tracking subsystem is essential to 1) the precision measurement of muons, especially at low energies, 2) the charge sign determination of particles with energies as high as 2 TeV, 3) the jet, B-physics, and top quark studies, especially while the LHC is initially operating at low luminosities, and 4) the rejection of background events in the search for the Higgs and other new physics such as supersymmetry.
The Inner Tracker is a highly complex and challenging part of the CMS experiment that will be difficult to construct. Major technological advances will be needed to achieve the extremely high resolution position measurements required, and to deal with the high radiation levels and high particle fluxes that will be present. Advances must be made in detector manufacturing and design, in front-end electronics, and in the areas of support structures, services, and system integration, all of which are key elements in such a large and highly complex tracking system.
Continued advances in the area of Inner Tracking are very important to the future of the US HEP program, and improvements to tracking detector techniques are a major part of all US colliding beam efforts. Advancements in every area of tracking detector design will be necessary in order to achieve the goals of the CMS Inner Tracker design. Participation in the LHC Inner Tracking effort offers the greatest opportunity for advancement in each of the areas mentioned above.
Because of the history and experience of the US high energy physics groups interested in the CMS Tracking effort, we are poised to make significant contributions to the LHC program. Largely through efforts for the SSC, CDF, and D0, the US tracking group has developed considerable practical expertise and has made significant progress in developing tracking detector subsystems for high rate experiments in high luminosity collider facilities. In the experience of operating and analyzing data from the existing Silicon Vertex Detector (SVX) at Fermilab, in the design and prototyping of upgrades for the CDF and D0 tracking systems, in the work done under the SSC Generic R&DProgram, and the subsequent work in the SDC and GEM collaborations, robust fine-grained tracking systems are at an advanced stage of development.
The requirements for the LHC tracking systems are, however, even more severe than for the SSC, given the 10 times higher luminosity at which the LHC will be required to operate. This increase in luminosity translates directly into increases in radiation damage, detector occupancy, and required background rejection capabilities. A great deal of further R&Dwill be required to meet the CMS tracking system challenge.
The US will play a very significant role in the CMS Inner Tracking subsystem. Starting with extensive simulation work, including studies of such topics as optimal tracking detector configuration, physics performance potential, and pattern recognition techniques, we will provide significant input to the Inner Tracking effort. We have detector expertise in all technologies planned for CMS (pixels, silicon strip, and gas microstrip) and will further develop that expertise as part of the CMS effort. Where appropriate, and in consultation with the full CMS tracking group, we will seek to incorporate that detector technology and the front-end, readout, and hybrid technologies that were developed for the SSC into the CMS tracking system design. We can provide a wealth of practical information that may be crucial to the design derived from the operation of the silicon (and other) tracking systems at Fermilab, and from upgrades in progress there. However, the largest responsibility of the US tracking team will be in the area of mechanical engineering and system integration of the Inner Tracker. As such, we would be responsible for the backbone of this essential portion of the CMS detector.
List of Interested Groups: